JPS607267A - Original picture information reading and processing device - Google Patents

Abstract

PURPOSE:To improve the reproducibility of gray color gradation in a reproduced picture by providing a digital pulse width converter converting an output digital signal of an analog digital converter into a pulse width according to the relation of a scheduled function. CONSTITUTION:The analog digital converter 17 converts an analog picture signal (a) into a digital value based on a shading distortion correcting signal (d). A picture signal (e) converted digitally is applied to a storage device 18 as a read address. Then a memory cell corresponding to the digital picture signal value at that time is selected in the storage device 18. On the other hand, a pulse oscillator 19 is connected to a clock input terminal of a binary counter 20. Each frequency dividing output signal (e.g., 1/2, 1/4, 1/8 and 1/16 frequency dividing output) of the binary counter 20 is fed to the storage device 18 as another read address of the storage device 18.

Description

[Detailed Description of the Invention] (Field of Application) This defense is based on Nono Kushimiri et al.
It is related to the V-len method (original image information reading processing device that reads two signals. The present invention relates to an information reading processing device.

(Prior Art) The schematic structure of a commonly used original image information reading processor is shown in FIG. 5, and its operation will be explained below.

The document 2 on the original {^l~ray 1 is moved to the document feed roll 3Δ.
3B and 3C (the originals are sent out one by one and conveyed onto the platen glass 5.The originals on the platen glass 5 are
Receives 4 irradiation with fluorescence. The reflected light from the original 2 is imaged by an imaging lens 6 onto a C-optical-electrical converter 7 (for example, a CCD sensor). The optical-electrical converter 7 is controlled by an image signal processing circuit 8 , converts the image information on the original 2 into an electrical signal.The electrical image signal, which is the read output of the optical-to-electrical converter 7, is input to an image signal processing circuit 8, and converted into a C2 rectangular signal by an appropriate method. converted and output.

The 1,000,000 manuscripts read in the above manner are obtained by optically reading the manuscript at a distance of 1 cm, as described above, by the original feeder. While only an analog image signal is available, a device that converts the gray gradation (intermediate) part of the image information reading IR analog output into 2 1 + i'i and transmits it is 2-dimensional. (2) A sum signal obtained by adding a sawtooth wave to an anault I1 image signal. An apparatus is known in which a pseudo halftone signal is obtained by comparing the analog image signal level with a predetermined threshold level and converting the analog image signal level into a pulse width.

However, with D1F processing, the number of memory cruisers required to store image information increases, and the processing becomes complicated, resulting in longer processing times and higher costs.
It had drawbacks such as not being suitable for high-speed transmission.

In the latter case due to the sawtooth wave, (1) shading distortion included in the image information (emission intensity decreases at both ends compared to the center part of the fluorescent lamp used as a light source for illuminating the original); OJ: Because of the decrease in the previous set at the periphery of the condensing lens, when reading the same white document, the level of the analog image signal is 1.
J
; As a result, the uniformity of the reproduced image density deteriorates, causing white background stains, and (2) the maximum amplitude of the analog image signal changes and the gray reproducibility deteriorates. , the white background becomes dirty, (3) the circuit configuration for creating the sawtooth wave is complicated, and (4) it is difficult to create a sawtooth wave with a slope that substantially overlaps the desired conversion function. They had drawbacks such as it was difficult to change the conversion function, and it was virtually impossible to change the conversion function.Also, both had the drawback of lack of design flexibility.

(Purpose) The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to appropriately perform the gray level i1# processing of the original {4-picture information} and to remove the gray level i1# of the original image information. It is an object of the present invention to provide a small and inexpensive document image information reading and processing device that improves gradation reproducibility.

(Summary) In order to achieve the above object, the present invention provides an af UI digital conversion method that converts an output signal of an image information reading device that converts optical image information into an analog signal into a digital signal. and a digital-pulse width conversion 2:; for converting the output digital signal of this analog 1 cog-digital converter into a pulse width according to a predetermined functional relationship. There are characteristics.

Furthermore, (42) the present invention has the following features: 1) A plurality of predetermined function relationships described in C1 are prepared, and the functional relationship for digital signal-pulse width conversion can be appropriately selected. Features are d9.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the invention, and FIG. 2 is a timing block diagram 17-1 for explaining its operation.

A time-series analog image signal a read every 1 scan is sent to a known appropriate image information reading device @11 and supplied to a peak hold circuit 25, a digital converter 17, and a digital converter 17. be done.

Peak hold circuit 251;
It holds the lE value (peak voltage) and outputs 1- (signal 1+ in Figure 2). A shading distortion inverse signal generator 27 outputs a signal for C distortion correction (signal C in FIG. 2) in synchronization with the reading main scan.

The peak voltage of the analog signal a is combined with the distortion correction signal C in the multiplier 2G, and the peak voltage of the analog signal a is -signal d.

Analog-digital conversion""a 17 P is the front
: Shading correction j [based on signal d, j
′) Convert 11g artist number a to j゛digital value.

For example, in order to do this, (1) First, the shading distortion correction signal d and
Analog signals with 1 shading distortion corrected by 'flifling the 1st image signal a and
(2) Convert this to digital formatting (1 in Figure 2 is number O).

F+: /, :, As another method of analog-to-digital conversion, a person skilled in the art can easily use the shading distortion correction signal itself obtained by inverting the shading distortion correction signal d as the conversion reference level. There must be C that can be understood.

Of course, if shading distortion can be sufficiently reduced by improving the illumination light source or condensing optical system, shading distortion correction will become unnecessary.

The digital converter 17 converts the analog image signal a directly into -C digital values using the usual method W! All you have to do is swoon.

Both digitally converted signals e are as follows:
Provided as a read address. As a result, note 11
Within the HfTT 18, a memory cell corresponding to the digital image signal value at that time is selected.

On the other hand, the pulse oscillator 19 is connected to the clock input terminal of the binary counter 20. Each frequency division output signal of the binary counter 20! i3 (for example 1/2.1/4.
1/8 and 1/16 frequency division output horn) is used as another read address of the storage device 18 and is supplied to the storage device 18.

That is, as described above, the memory cell selected by -C is selected according to the output value of the digital image signal at that time, and further, according to the output value of the binary counter 2o,
Select addresses in a circular manner.

Therefore, as is clear, the binary counter 20
It is desirable that the digital image signal output from the analog-to-digital converter 17 is held constant until the output reaches the minimum value.

To this end, as shown in FIG. Even if you temporarily memorize the appearance. FIG. 2f shows the latch timing in the above case.

Note that in this specification C, the read address supplied from the binary counter 20 is referred to as a circular address signal.

An example of the memory map of the storage device 18 is shown in Table 1.

In this example, a 3-bit counter is used as the binary counter 20, and both signals are also digitized in 8 stages of 3 bits.

It is clear from this table that the memory cell groups corresponding to λ・1 for each of J, Uni, and DEC Dikuru 1ijii Shinyumi (Table 1 (t, each memory area in one horizontal column) are as follows: A signal with a ratio of l-levels proportional to the digital value (1 in the table)
?l') and an L level signal (indicated by 0'' in the table) are stored in advance.

Depending on the digital output value of the digital converter 17, a particular memory field in the device '18 is selected, -h, the circular address (i
``J'' is read out from the selected memory cell.

With this 1J, the output terminal of the memory direct 18 is
21 of the time series that determines the pulse width according to the digital value
The ff signal (transmission g in FIG. 2) is output.

In this case, the conversion function C between the output of the pulse width and the human power of the digital image transmission, as shown in FIG. Logarithmic function, exponential function, and (tl) are considered.Which one or more of these conversion functions to adopt depends on the shape of the driver 1 that forms the reproduced image. ,
You can decide the concentration depending on what you want.

This pulse signal g is wrapped in a wrap circuit 23 by a latch signal 11 (FIG. 2) with a period corresponding to the pixel interval on the printer (shown in the figure), and is applied to each signal electrode of the printer.

Therefore, if the printer is controlled so that printing is not performed at the end of the output horn signal II 1 II, but printing is performed when the output signal is II OII, one line of waveform 1 (as shown in FIG. will be printed.

In addition to the above J and Una method, J2C1 is shown in a or aC in Figure 2! For I information,
This results in a printed or reproduced image with good gray-tone (half-tone) reproducibility, similar to the halftone dots used in the 111 printing technique.

The line synchronization pulse generator 21 generates a reline synchronization pulse, shown in FIG.

At this time, the stepping motor 1 (5) is intermittently energized to drive the recording paper (not shown) line by line in the sub-scanning direction.

As shown in step C, the gray gradation (intermediate) level portion as well as the white J3 and black level portions of the original image will be reproduced with the number of dots corresponding to each level. .

As is clear, in FIG. 1, the storage device 1
8 is shown as having multiple output lines, this is not necessarily necessary.

However, J in Table 1: Eel, image signal digital value 63
, l and counter output as parameters are provided in correspondence with the scale conversion functions as shown in Fig. 3. If the conversion function is selected appropriately, the reproduced image is It is possible to switch the properties of the images, and to obtain the optimum reproduced image according to the application.

Furthermore, as will be described in detail below, if the conversion function is switched for each adjacent scan, a set of dots (for example, one corresponding to one dot Ijλ added to J3L for halftone dot printing) can be obtained. The shape of the image can be made closer to a circle, making it possible to reproduce more natural midtones.

An example of pulse width conversion for the analog image signal level for this purpose is shown in FIG. In the figure, C1 waveform aC indicates an analog picture signal, and 1:1 to 4 indicate pulse signals generated corresponding to the analog picture signal, respectively.

That is, F1-F4 correspond to the plurality of conversion functions previously described with respect to FIG. In the first and fourth memory maps, the pulse width for the same ablation image signal level is set to be relatively narrow, as shown in F 1 A3 and F/I, and in the second and third memory maps, F 2 J3 J: As shown by F3,
The pulse width for both the same analog signal levels is set relatively wide.

Then, the above ]=1 to ]=4 are stored in the storage device 18 in FIG.
It is configured such that the output lines are respectively output to four output lines, and the output lines are switched for each scanning line by the digital collector 22 (, -).

According to this configuration, when the analog image signal levels of corresponding pixel positions on four consecutive scanning lines are equal, the first
On the first and fourth scanning lines, a relatively small number of continuous dots 1 are printed, and on the second and third scanning lines between them, a relatively large number of continuous dots are printed, so the entire dot is circular. Drawers 1 to 1, which are close to , will be printed.

In addition, there are several hundred items 71 of reproduced images.

'tj, in 1- below, when converting 1゛digital 11C1 to pulse width, J: sea urchin shown in Table 11, output I
I II II consecutively indigenous [! , as shown by waveform q in Figure 2, we have described an example in which one pulse with a pulse width that is a function of a digital value generates 5, but this defense is not limited to this. do not have.

In other words, in general, the number of 111 II generated within one conversion period (in other words, within the time from when the binary counter 20 is reset to when it goes up) is a function of the digital value. For example, instead of setting the content for the digital value r011J in Table 1 as [0011100J, it may be set as rolololoJ.

(Effects) As is clear from the above explanation, according to the present defense, the following effects are achieved.

(1) Since the digital pulse width is converted by digital processing, it is possible to speed up the conversion and increase the reading speed.

(2) C memory rails are provided according to both digitized signal outputs, and these are addressed by the counter output, and the data is read out using the conversion function (i.e.,
Image reproduction characteristics) can be easily set and changed.

(3) In digital processing, the C1 conversion function that converts digital values to pulse widths does not change during operation, improving image reproducibility.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a timing chip 17-1 for explaining the operation of FIG. 1.
FIG. 3 is a graph showing an example of an analog-to-digital conversion function that can be clearly used in this invention.
Tizing CH 1 shows an example of the relationship between a group of analog signals and pulse width when using multiple conversion functions. -g, 5th
The figure is a side view showing a schematic configuration of a general document image information reading device. 11... Image information reading device, 16... Swapping motor, 17... Good digital converter, 18
...Storage device, 19...Pulse oscillator, 20...
Byte tree counter, 21... Line synchronous pulse oscillator, 22... γ (digital reflector, 23... Wrap-125... Peak hold times 8.26... Heavy mouth device, 2 '7...・Shading distortion reverse signal

Claims (4)

[Claims] (1) An image information reading device that reads the original in a raster skillen method and outputs both electrical and analog signals having levels corresponding to the shading of the original image, and an analog-digital device that converts the electrical analog image signal into a digital signal. a converter, a plurality of memory cells storing predetermined binary signal sequences for each of the digital signals, and a cyclic address signal for cyclically specifying a read address of each of the memory cells. A document image information reading and processing device i/, +, characterized in that it comprises a generating means, and a means for wrapping the readout signal from each of the memory cells with the dot printing cycle C° of the printer and outputting the same. . (2) The electrical anno-1 and lg image signals have been corrected for shading distortion! I! The original image information reading process 44'fqf described in claim 1 of the above claims. (3) An image information reading device that reads the original in a raster scan method and outputs an electrical analog image signal having a level corresponding to the density of the original image, and converts the electrical analog image signal into a digital signal. A plurality of analog-to-digital converters are provided for one value of the digital signal (No. 3), each recording a predetermined binary signal sequence.
a plurality of memory cells for J3, means for selecting one memory cell for each of the digital signals, and a cyclic address signal generating means for cyclically specifying a read address of each of the memory cells; A document image information reading and processing device characterized by comprising means for latching and outputting the readout number fi from each memory cell at a print cycle of a printer. (4) A patent reading processing apparatus characterized in that the electric blog image signal is corrected for shading distortion.